Table 4-2. Troubleshooting Table - continued.
TEST OR INSPECTION
4. FOUR MODULE (MOD) FAILURES SAME DRAWER ASSEMBLY continued.
Using VOM, check for 120 Vac at drawer assembly direct current (DC) power supply.
If 120 Vac is present go to step 7, otherwise refer to paragraph 4.6.4 and replace power cord assembly.
Check drawer assembly DC power supply fuse.
If fuse is not damaged go to step 8, otherwise replace fuse.
Using VOM, check DC power supply +5 Vdc output.
If +5 Vdc is present go to step 9, otherwise refer to paragraph 4.6.10 and replace DC power supply.
Disconnect connector P1 from connector J21 on left backplane and connector P2 from connector J21 on
right backplane. Using VOM, check for +5 Vdc on connector P1 and P2 at pins 3 (white lead) and 4
ground (black lead on connector P1 and black and green leads on connector P2).
If +5 Vdc is present go to step 10, otherwise refer to paragraph 4.6.4 and replace power cable assembly.
Is second drawer assembly operational? If second drawer assembly is operational go to step 11,
otherwise go to step 13.
Refer to paragraph 4.6.5 and replace RX-TX cable assembly.
If module COM failures are still present on monitor area status screen go to step 12.
Refer to paragraph 4.6.12 and replace input/output CCA.
If module COM failures are still present on monitor area status screen go to step 13.
Refer to paragraph 4.6.15 and replace or repair RS-485 cable assembly.
If module COM failures are still present on monitor area status screen refer to paragraph 4.6.14 and
replace communications CCA.
5. COM FAILURE INDICATED ON MONITOR AREA STATUS SCREEN FOR ALL MODULES.
A volt ohm meter (VOM) is required for this procedure.
Using VOM check for +5 Vdc, at +5 Vdc terminal, on any central processing unit (CPU) CCA.
If +5 Vdc is present go to step 2, otherwise perform troubleshooting procedure 4 step 2.